This invention relates generally to electroactive polymers. More particularly, the invention pertains to dual purpose electroactive copolymers, preparation thereof, and use in the manufacture of various types of opto-electronic devices.
Electroactive polymers are frequently used in a number of optical and electronic applications such as in light emitting diodes (xe2x80x9cLEDsxe2x80x9d), photovoltaic energy converters, photodetectors, photoconductors, e.g., in electrophotography, and in chemical and biochemical sensors. In each of these applications, it is often necessary to use a multiplicity of electroactive polymeric materials each having a different function in the device. For example, different polymeric materials are normally used to provide electron and/or hole charge transport, luminescence, photo-induced charge generation, and charge blocking or storage. By working with a number of structurally and functionally distinct polymers, one can achieve optimization of these separate functions.
It would be desirable, however, to reduce the number of polymeric materials needed in any particular opto-electronic device. In this way, the manufacture of opto-electronic devices is simplified by reducing the time, cost and number of materials involved in device fabrication.
The present invention is addressed to the aforementioned need in the art. A new class of electroactive polymers is now provided, comprising copolymers in which discrete and functionally unique segments present in a single polymer render the polymer multifunctional in nature. In a preferred embodiment, the electroactive copolymers are xe2x80x9cdual usexe2x80x9d polymers by virtue of containing both a charge transport segment and a light emissive segment. The invention represents an important advance in the art, insofar as the number of polymeric materials previously required in the manufacture of opto-electronic devices may now be significantly reduced. That is, with the present invention, fewer discrete and functionally unique polymeric layers are now necessary to provide all of the desired functions, e.g., electron transport, hole transport, light emission, and the like.
Accordingly, it is a primary object of the invention to address the above-mentioned need in the art by providing a dual purpose electroactive copolymer useful in the manufacture of an opto-electronic device.
It is another object of the invention to provide such a copolymer which comprises a charge transporting polymeric segment and a light emitting polymeric segment.
It is still another object of the invention to provide such a copolymer in the form of an A-B-A triblock copolymer.
It is yet another object of the invention to provide such a copolymer in the form of a brush-type graft copolymer.
It is an additional object of the invention to provide methods for synthesizing dual use electroactive polymers as disclosed and claimed herein.
It is still an additional object of the invention to provide opto-electronic devices, particularly LEDs, fabricated with a dual use electroactive copolymer as disclosed and claimed herein.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention.